Add separate feature flag for VR CCT browsing.

chrome/browser/flag_descriptions.cc

Index: chrome/browser/flag_descriptions.cc
diff --git a/chrome/browser/flag_descriptions.cc b/chrome/browser/flag_descriptions.cc
index 277b9c1e9ff9281979aaaaa8988a8be988123b55..cff09c4f2a8c1cd31622e8a95bdd0f3027ca0a6b 100644
--- a/chrome/browser/flag_descriptions.cc
+++ b/chrome/browser/flag_descriptions.cc
@@ -2532,6 +2532,12 @@ const char kEnableVrShellName[] = "Enable Chrome VR.";
 const char kEnableVrShellDescription[] =
     "Allow browsing with a VR headset if available for this device.";
 
+const char kVrCustomTabBrowsingName[] = "Enable Custom Tab browsing in VR.";
+
+const char kVrCustomTabBrowsingDescription[] =
+    "Allow browsing with a VR headset in a Custom Tab if available for this "
+    "device.";
+
 #endif  // defined(OS_ANDROID)
 
 //  Web payments